1. Field of the Invention
The present invention relates to a paintwork coating composition and to a coating cloth and, more particularly, to a paintwork coating composition to coat a paintwork in a vehicle and the like and to a coating cloth.
2. Description of Background Art
Car waxes have been widely used for coating a paintwork in a vehicle. Usually, the car wax comprises a mixture of a wax component to protect and polish a paintwork in a vehicle and a silicone oil to provide a water-repellent property to the paintwork. A variety of car waxes having various properties are known, including cake, paste-form wax and liquid-form wax.
Some car waxes use a wax component that is subjected to fouling, depending on its composition and content. For improvement in antifouling of a paintwork, for example, Japanese Patent Publication No. Hei 6(1994)-13,663 proposed a coating treatment comprising 1-50 weight % of low molecular weight polytetrafluoroethylene having a molecular weight of 1,000 to 100,000 and 0.1-25 weight % of perfluoropolyether.
Fluorochemical wax is superior to silicon wax in antifouling property of the coated paintwork. In view of this, for example, Japanese Laid-open (Unexamined) Patent Publication No. Hei 5 (1993)-130,963 proposed a car wax-applying wet sheet comprising a non-woven fabric sheet wetted by a fluorochemical wax.
Meanwhile, in recent years, the so-called dry bright type of car waxes requiring no wiping of wax after applied to the paintwork are becoming widely used. Since the dry bright type of car wax requires no wiping of wax, it has the advantage that the waxing can be done in a simple work and in a short time.
The coating treatment disclosed by Japanese Patent Publication No. Hei 6(1994)-13,663 cited above uses an organic solvent, such as naphtha for industrial use, as dispersion solvent of polytetrafluoroethylene and perfluoropolyether, as referred to in the examples, and as such is not really desirable for the environments and the humans.
With this coating treatment, when the wax is applied to the paintwork, the quantity of adherence of wax to the paintwork per quantity of wax applied thereto is small. Accordingly, a large quantity of wax is practically required for the application of the wax to the paintwork and, after the waxing, the wiping of the wax is required. Consequently, it is difficult to apply this coating treatment to the dry bright type of wax requiring a small quantity of wax and requiring no wiping of the wax.
Further, the fluorochemical wax has a good antifouling property of the coating of paintwork, but even the fluorochemical wax having the same components may fail to form a good coating on the paintwork, depending upon the type of cloth used, so that the water-repellent property and the antifouling property may reduce.
In the dry bright type wax, in particular, the cloth used reflects on the waxing performance significantly, because a small quantity of wax is applied to the paintwork and also there is a need to eliminate the wiping of the wax after the application of wax.
It is an object of the invention to provide a paintwork coating composition that is harmless to the environments and humans and enables the paintwork to be fully coated by the application of only a small quantity of coating composition. It is another object of the invention to provide a coating cloth that provides a smooth rubbing work in the coating process and can develop a good water-repellent property and a good antifouling property.
The present invention provides a novel paintwork coating composition comprising water dispersion comprising polytetrafuluoroethylene and perfluoropolyether.
According to the paintwork coating composition of the present invention, the quantity of adherence of the coating composition to the paintwork per quantity of coating composition applied thereto is large. Therefore, the coating composition of the present invention can suitably be used as the coating composition of the dry bright type requiring no wipe after a small quantity of coating composition is rubbed thereon. Further, since the paintwork coating composition of the present invention is water dispersion, good working conditions harmless to environments and humans can be ensured. Thus, the coating composition of the present invention is harmless to the environments and humans and also can be effectively used as the non-wipe coating composition for simplifying the coating work and finishing it in a short time.
In the paintwork coating composition of the present invention, it is preferable that the water dispersion of polytetrafluoroethylene and the water dispersion of perfluoropolyether are mixed.
In the paintwork coating composition of the present invention, it is preferable that the content of polytetrafluoroethylene is not more than 0.8 weight % per total quantity of paintwork coating composition.
In the paint coating composition of the present invention, it is preferable that a hydrophilic organic modified silicone oil is further mixed. It is preferable that the hydrophilic organic modified silicone oil is polyether modified silicone oil.
In the paintwork coating composition of the present invention, it is preferable that ion cross-linked organic acids is further mixed as a thickening agent.
The present invention provides a novel coating cloth wherein a coating composition comprising polytetrafluoroethylene and perfluoropolyether is impregnated in a cloth having a basis weight of 30-300 g/m2 and a density of 0.02-0.3 g/cm3 under load condition of 1.961 KPa.
According to the coating cloth of the present invention, the smooth rubbing work in the coating process can be ensured and also the coating having little unevenness can be formed on the paintwork, so that the good water-repellent property and the good antifouling property are developed. Particularly, when the coating composition is impregnated in the cloth in the form of water dispersion, polytetrafluoroethylene and perfluoropolyether are stably dispersed in water before the rubbing of the coating composition, while, once the coating composition is rubbed over the paintwork, they are allowed to adequately adhere to the paintwork by the rubbing force and are hardly reverted into water. Consequently, the quantity of adherence of the coating composition to the paintwork per quantity of coating composition applied thereto is large. Therefore, the coating cloth of the present invention can suitably be used as the coating cloth of the dry bright type requiring no wipe after a small quantity of coating composition is rubbed thereon. Further, the cloth impregnated with the coating composition can dispense with the organic solvent, so good working conditions for environments and humans can be ensured.
In the coating cloth of the present invention, it is preferable that the coating composition is water dispersion comprising polytetrafluoroethylene and perfluoropolyether. Also, it is preferable that the content of polytetrafluoroethylene in the coating composition is not more than 0.8 weight %.
In the coating cloth of the present invention, it is preferable that a hydrophilic organic modified silicone oil, or polyether modified silicone oil, in particular, is further mixed in the coating composition. Also, it is preferable that ion cross-linked organic acids is further mixed in the coating composition as a thickening agent.
A paintwork coating composition of the present invention (hereinafter it is simply referred to as xe2x80x9cthe coating compositionxe2x80x9d, which is equivalent to xe2x80x9cthe paintwork coating compositionxe2x80x9d, unless otherwise specified.) comprises water dispersion comprising polytetrafluoroethylene and perfluoropolyether.
Polytetrafluoroethylene (hereinafter it is sometimes abbreviated to PTFE) can be produced, for example, by polymerizing tetraethylene fluoride in a known manner. Polytetrafluoroethylene having a number average molecular weight of 1,000 to 1,000,000 or preferably of 3,000 to 500,000 is preferably used. Polytetrafluoroethylenes that may be used include commercially available products, such as Lubron L Series (available from Daikin Industries, Ltd., PTFE powder), Fluon L Series (available from Asahi I.C.I. Fluoropolymers Co., Ltd., PTFE powder), Fluon CD Series (available from Asahi Glass Co., Ltd., PTFE powder), Hostaflon Series (available from Dyneon, PTFE powder), Teflon TFE (available from Du Pont-Mitsui Fluorochemicals Co., Ltd., PTFE powder), KTL, KT Series (available from Kitamura Ltd., PTFE powder), Cefral lube (available from Central Glass Co., Ltd., PTFE powder) and Algoflon (available from Ausimont K.K., PTFE powder).
Perfluoropolyethers that may be used include polymers and their derivatives having the structure of the following formulas (1) to (4), which can be produced by a known method, such as by ring-opening addition polymerization of perfluoroalkylene oxide or by irradiation of perfluoroalkenes with ultraviolet. 
(In the formulas (1)-(4) given above, m represents an integer of 1-300 and n represents an integer of 1-210)
Perfluoropolyether having a number average molecular weight of 400 to 20,000 or preferably of 1,000 to 15,000 is preferably used. Commercially available products may be used as the perfluoropolyether. For example, KRYTOX Series (available from Du Pont de Numours and Co.) can be cited as equivalent of the one having the structural formula (1); FOMBLIN Series, Y-type (available from Ausimont K.K.) can be cited as equivalent of the one having the structural formula (2); FOMBLIN Series, M-type and Z-type (available from Ausimont K.K.) can be cited as equivalent of the one having the structural formula (3); and DEMNUM Series (available from Daikin Industries, Ltd.) can be cited as equivalent of the one having the structural formula (4).
The coating composition of the present invention can be produced by dispersing polytetrafluoroethylene and perfluoropolyether in water. The dispersion of polytetrafluoroethylene and perfluoropolyether in water can be obtained, for example, by mixing and agitating polytetrafluoroethylene, perfluoropolyether and a dispersing agent and then adding water to the mixture, to forcibly disperse them in water.
Dispersing agents that may be used include, for example, (i) anionic surface active agents typified by Na, K, Li, ammonia, morpholine and alkanolamine salt, such as higher fatty acid salt including oleic acid, alkylbenzene sulfonate, alkyl sulfate, polyoxyalkyl sulfate and alkan sulfonate, (ii) nonionic surface active agents typified by polyoxyethylene derivatives, such as polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyhydric alcohol fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid ester, oxyethylene oxypropylene block polymer, fatty acid alkanolamide, amine oxide and others, (iii) cationic surface active agents typified by alkylamine salt and quaternary ammonium salt, etc., (iv) amphoteric ionic surface active agents typified by e.g. alkylbetaine, and (v) polyacrylic acid salt typified by e.g. polyacrylic acid ammonium. In addition, commonly used surface active agents, such as fluorochemical surface active agent and silicon surface active agent, having the emulsification property and the solubilization and dispersion property may be used. For example, polyacrylic acid salt is preferably used, though it depends upon its intended purposes and applications.
For example, 0.01-0.8 weight %, or preferably 0.05-0.5 weight %, of polytetrafluoroethylene, 0.01-5.0 weight %, or preferably 0.1-2.0 weight %, of perfluoropolyether, and 0.01-10.0 weight %, or preferably 0.1-5.0 weight %, of dispersing agent are mixed per the total quantity of water dispersion and, then, the mixture is added into water and agitated to be forcibly dispersed in water. The quantity used can be reduced by using the fluorochemical surface active agent.
The water dispersion thus obtained takes the state in which polytetrafluoroethylene and perfluoropolyether are dispersed in water in an emulsified form or in a suspended form. When the water dispersion takes the state in which they are dispersed in water in the emulsified form, a stable oil-in-water (O/W) emulsion is formed in which polytetrafluoroethylene and perfluoropolyether exist in micelle. When the water dispersion takes the state in which they are dispersed in water in the suspended form, a stable suspension is formed in which polytetrafluoroethylene and perfluoropolyether are dispersed in a block form or in an oil spot form.
While the coating composition of the present invention may be produced by forcibly dispersing polytetrafluoroethylene and perfluoropolyether in water, it is further preferable that the water dispersion comprising polytetrafluoroethylene and perfluoropolyether is produced by mixing the water dispersion of polytetrafluoroethylene as was prepared in advance and the water dispersion of perfluoropolyether as was prepared in advance.
The mixing of the water dispersion of polytetrafluoroethylene and the water dispersion of perfluoropolyether takes the state in which polytetrafluoroethylene and perfluoropolyether are separately dispersed in water in the emulsified form or in the suspended form. When the water dispersion takes the state in which they are dispersed in water in the emulsified form, a stable mixed solution of oil-in-water (O/W) emulsion is formed in which polytetrafluoroethylene and perfluoropolyether separately exist in micelle. When the water dispersion takes the state in which they are dispersed in water in the suspended form, a stable mixed solution of suspension is formed in which polytetrafluoroethylene and perfluoropolyether are separately dispersed in a block form or in an oil spot form.
The coating composition of the present invention comprising the mixture of the water dispersion of polytetrafluoroethylene and the water dispersion of perfluoropolyether has the characteristic feature that polytetrafluoroethylene and perfluoropolyether are kept in the state of being separately and stably dispersed in water, before the rubbing of the coating composition, while, at the time of the rubbing of the coating composition, they are mixed with each other while being adhesively rubbed on the paintwork by the rubbing force. Consequently, a smooth rubbing work in the coating process can be ensured and also a good coating of even in coating thickness can be obtained, as compared with the coating composition comprising polytetrafluoroethylene and perfluoropolyether which are forcibly dispersed from the beginning.
The water dispersion of polytetrafluoroethylene can be obtained as the water dispersion of polytetrafluoroethylene as it is by a known process such as a solution polymerization process or an emulsion polymerization process.
The water dispersions of polytetrafluoroethylene that may be used include commercially available products, such as KRYTOX DF/W (available from Du Pont de Numours and Co., PTFE emulsion with a solid content of 20 weight % and a number average molecular weight of 3,500), KRYTOX LW-1,200 (available from Du Pont de Numours and Co., PTFE emulsion with a solid content of 20 weight % and a number average molecular weight of 40,000), Fluon AD Series (available from Asahi I.C.I. Fluoropolymers Co., Ltd., PTFE dispersion), Hostaflon 5,000 Series (available from Dyneon, PTFE dispersion), and Lubron LDW-40 (available from Daikin Industries, Ltd., PTFE dispersion).
The water dispersion of perfluoropolyether can also be obtained, for example, by the emulsion polymerization process or the forcible dispersion process, as is the case with the process above. The water dispersion of perfluoropolyether that may be used include commercially available products. Of the commercially available products cited above, L-205 (available from Chukyo Yushi K.K., perfluoropolyether emulsion, a nonvolatile content of 64 weight %), K-926 (available from Chukyo Yushi K.K., perfluoropolyether emulsion, a nonvolatile content of 64 weight %), L-287 (available from Chukyo Yushi K.K., perfluoropolyether emulsion, a nonvolatile content of 64 weight %), NIKKOL NET-HC Series (available from Nikko Chemicals Co., Ltd., perfluoropolyether emulsion), NIKKOL NET-U Series (available from Nikko Chemicals Co., Ltd., perfluoropolyether emulsion), and FOMBLIN Emulsion FE-20 Series (available from Ausimont K.K., perfluoropolyether emulsion) can be cited, for example.
The coating composition of the present invention thus obtained is preferably prepared so that polytetrafluoroethylene of a solid content of not more than 0.8 weight %, or preferably not more than 0.5 weight %, or particularly 0.05-0.5 weight % can be contained in the water dispersion comprising polytetrafluoroethylene and perfluoropolyether (or in the total quantity of coating composition when various components are mixed therein, as will be mentioned later). With not more than 0.8 weight % of polytetrafluoroethylene, the coating composition can be effectively applied to the dry bright type of car wax requiring only a small quantity of wax to be rubbed on the paintwork and no wiping, as mentioned later.
In addition, the coating composition of the present invention is preferably prepared so that 0.01-5.0 weight %, or preferably 0.1-2.0 weight %, of perfluoropolyether is contained in the water dispersion comprising polytetrafluoroethylene and perfluoropolyether (or in the total quantity of coating composition when various components are mixed therein, as will be mentioned later). With not more than 0.01 weight % of perfluoropolyether, there is the possibility that sufficient polishing and water-repellent and oil-repellent properties may not be obtained. With not less than 5.0 weight % of perfluoropolyether, there is the possibility that the oil may remain excessively on the paintwork, which may cause unevenness in coating thickness.
In the coating composition of the present invention, organic modified silicone oil may further be mixed. Organic modified silicone oils that may be used include, for example, (i) hydrophobic organic modified silicone oils, such as dimethyl silicone oil, methylphenyl silicone oil, methylhydrodiene silicone oil, alkyl modified silicone oil, alkylaralkyl modified silicone oil, fluorine modified silicone oil, epoxy modified silicone oil, epoxypolyether modified silicone oil, phenol modified silicone oil and acryl modified silicone oil, (ii) hydrophilic organic modified silicone oil, such as polyether modified silicone oil, alcohol modified silicone oil, amino modified silicone oil, carboxyl modified silicone oil and mercapto modified silicone oil, and (iii) other modified silicone oils into which various organic functional groups are introduced. The organic modified silicone oils may be used singularly or in combination of two or more. It is to be noted that the hydrophobic organic modified silicone oils and the hydrophilic organic modified silicone oil cited above are classified under common methods of classification. To be more specific, the belonging to the hydrophobic organic modified silicone oils or the hydrophilic organic modified silicone oil is determined properly under a ratio of modification of hydrophilic group and hydrophobic group.
Of these, the hydrophilic organic modified silicone oil is preferably used in the coating composition of the present invention. More specifically, nonionic organic modified silicone oil, such as polyether modified silicone oil, and ionic organic modified silicone oil, such as amino modified silicone oil and carboxyl modified silicone oil, are preferably used in the coating composition of the present invention. When hydrophilic organic modified silicone oil is mixed in the coating composition, the smooth rubbing work in the coating process can be ensured and also the good coating of even in coating thickness can be obtained. Particularly when the polyether modified silicone oil is mixed in the coating composition, that effect is significantly developed.
Polyether modified silicone oils that may be used include, for example, (i) silicone oils with modified polyether in which polysiloxane is modified with polyoxyalkylene, such as dimethylsiloxane.methyl(polyoxyethylene)siloxane copolymer, dimethylsiloxane.methyl(polyoxyethylene.polyoxypropylene)siloxane copolymer, and polyoxyethylene.methylpolysiloxane copolymer, and (ii) fluorine.polyether modified silicone oils modified by alkyl fluoride. For example, those having HLB (hydrophile-lipophile balance) of about 10 are preferably used.
Polyether modified silicone oils that may be used include commercially available products, such as KF-353, KF-618, KF-354 and KF-355 (available from Shin-Etsu Chemical Co., Ltd., polyether modified silicone), FPD Series (Shin-Etsu Chemical Co., Ltd., fluorine.polyether modified silicone), SH3746, SH3749, SH8400 and SH8410 (available from Dow Corning Toray Silicone Co., Ltd., polyether modified silicone), and L03 and L051 (Wacker Asahikasei Silicone Co., Ltd., polyether modified silicone).
The coating composition of the present invention is preferably prepared so that 0.01-3.0 weight %, or preferably 0.01-0.5 weight %, of organic modified silicone oil is contained in the total quantity of coating composition. With not more than 0.01 weight % of organic modified silicone oil, there is the possibility that at the time of rubbing of the wax, unevenness in coating thickness may be caused to hinder the smooth rubbing treatment. With not less than 3.0 weight % of organic modified silicone oil, the evenness in coating thickness can be provided, but the initial water-repellent and oil-repellent properties and the persistence may reduce.
In the coating composition of the present invention, wax, resin and thickening agent may preferably be mixed for the intended purposes and applications.
The waxes that may be used include, for example, (i) natural waxes typified by camauba wax, candelilla wax, montan wax, ceresin, paraffin, microcrystalline wax and ozokerite, (ii) acid waxes and ester waxes and derivatives thereof based on xcex1-olefin wax, Fischer-Tropsch wax and derivatives thereof polyolefin wax and derivatives thereof, paraffin oxide, microcrystalling wax oxide, castor wax and montan wax, (iii) wax-like material typified by lanolin derivatives, petroleum olefin-based olefin and malec acid anhydride or acrylic acid, waxes comprising vinyl acetate, metal soap, fat and oil, higher fatty acid, higher alcohol, hydrogenated oil, aliphatic acid amide and polyether, and (iv) a variety of modified waxes such as fluorine modified wax, silicone modified wax and resin modified wax. The wax mixed can provide improved coating or polishing of the paintwork. The wax is preferably used in the form of the water dispersion of the emulsion form or suspension form. The coating composition of the present invention is preferably prepared so that 0.01-5.0 weight %, or preferably 0.02-3.0 weight %, of wax is contained in the total quantity of coating composition.
The resins that may be used include, for example, silicone resin, fluorochemical resin, petroleum resin, terpene resin, alicyclic hydrocarbon resin, alkyd resin, polyamide resin, polyurethane resin, phenol resin, urea melamine resin, polyester resin, amino resin, melamine resin, acrylic resin, vinyl resin, urea resin, epoxy resin, rosin modified resin, amino alkyd resin, modified alkyd resin, natural resin, ketone resin and rosin resin. The resin may be used singularly or in combination of two or more. The resin mixed can provide improved grab. The resin is preferably used in the form of the water dispersion of the emulsion form or suspension form. The coating composition of the present invention is preferably prepared so that 0.01-3.0 weight %, or preferably 0.02-1.0 weight %, of resin is contained in the total quantity of coating composition.
The thickening agents that may be used include, for example, ion cross-linked organic acids, gums, minerals and celluloses. In addition to these, they also include agar, gelatin and polyacrylamide.
Examples of the ion cross-linked organic acids are organic acids, such as polyacrylic acid and alginic acid, in which ions are cross-linked by addition of salt, so that molecular chains are extended to develop the thickening property. For the polyacrylic acid, the salts added include, for example, inorganic alkalis, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate and ammonia, and alkalis including organic amines, such as monoethanolamine, diethanolamine, triethanolamine, triethylamine, di-isopropanolamine, di-(2-ethylhexyl)amine, aminomethylpropanol, tromethamine and tetrahydroxypropylethylene diamine. For the alginic acid, the salts added include, for example, divalent metallic salts, such as calcium chloride and magnesium chloride. These salts are used in equivalence required to neutralize the carboxylic acid of the organic acid.
The gums that may be used include, for example, gum arabic, Cyamoposis Gum and derivatives thereof, vee gum, xanthan gum, Welan gum, ramthan gum and gelan gum. The minerals that may be used include, for example, bentonite and montmorillonite. The celluloses that may be used include, for example, carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose. The thicknening agents may be used singularly or in combination of two or more. The mixture of the thickening agent can provide improved control of sediment of component and improved solution stability.
Of these, the ion cross-linked organic acids are preferably used in the coating composition of the present invention. The mixture of the ion cross-linked organic acids can develop water retention characteristics to improve workability, so that a good coating having even thickness can be realized.
The thickening agent is preferably adjusted so that when thickening agent is contained in the coating composition, the coating composition can have the viscosity of 0.05-200 Paxc2x7s, or preferably 0.180 Paxc2x7s.
Further, a variety of usually added additives, such as polishing agent, surface active agent, abrasive, dye, pigment, perfume agent, lubricant, ultraviolet absorption agent and oxidation inhibitor may be mixed in the coating composition of the present invention. For example, the mixture of lubricant, such as silicone powder and wax powder, can provide an improved wiping property.
In the coating composition of the present invention, the components cited above are mixed in water in the proportion mentioned above and agitated to be uniformly dispersed in water to thereby produce the water dispersion. It is to be noted that when the thickening agent is added, it can be mixed in the initial stage or last stage or in any selective stage of mixing the respective components, to thicken the coating composition of the present invention uniformly for improvement of viscosity thereof.
The coating composition of the present invention thus produced can be applied to the coating of paintworks in metals, plastics, ceramics and woods, without limiting to any specific paintwork. To be more specific, the coating composition of the present invention can be applied to the coating of paintworks in vehicles, aircrafts, boats and ships, heavy machinery, machines in various industries, furniture, electrical household appliances and electrical equipment, and a variety of household appliances.
When the paintwork is treated by use of the coating composition of the present invention, e.g. about 5-50 g, or preferably about 15-40 g, per square meter of coating composition can be used and rubbed over the paintwork with a cloth until the paintwork is cleaned up.
According to the coating composition of the present invention, polytetrafluoroethylene and perfluoropolyether are stably dispersed in water before the rubbing of the coating composition, while, once the coating composition is rubbed over the paintwork, they are allowed to adequately adhere to the paintwork by the rubbing force and are hardly reverted into water. Consequently, the quantity of adherence of the coating composition to the paintwork per quantity of coating composition applied thereto is large. Therefore, the coating composition of the present invention can suitably be used as the coating composition of the dry bright type requiring no wipe after a small quantity of coating composition is rubbed thereon.
Further, according to the coating composition of the present invention, water is used, instead of organic solvent, as the dispersion solvent of polytetrafluoroethylene and perfluoropolyether. Due to this, the coating composition is desirable for the environments and the humans, and good working conditions are ensured.
Thus, the coating composition of the present invention is harmless to the environments and humans and also can be effectively used as the non-wipe wax for simplifying the waxing work and finishing it in a short time.
In addition, the coating cloth of the present invention is formed by a cloth having a basis weight (unit representing mass per unit area of fabric, a gram number per square meter) of 30-300 g/m2 and a density of 0.02-0.3 g/cm3 under load condition of 1.961 KPa being impregnated with coating composition comprising polytetrafluoroethylene and perfluoropolyether (the coating composition defined herein is not limited to the coating composition above, as long as it comprises polytetrafluoroethylene and perfluoropolyether) or preferably with the same coating composition as above.
The cloth used in the present invention is a cloth having a basis weight of 30-300 g/m2, or preferably 40-200 g/m2, and a density of 0.02-0.3 g/cm3, or preferably 0.1-0.25 g/cm3, under load condition of 1.961 KPa.
With the cloth having a basis weight smaller than that, the thickness of the cloth is reduced excessively and thus the retention volume of the coating composition impregnated is reduced, so that the coating composition cannot be fully impregnated in the cloth. As a result of this, such a cloth cannot wax the paintwork to a sufficient extent. On the other hand, with the cloth having a basis weight larger than that, the thickness of the cloth is increased excessively and thus the processing of the cloth and the workability in the waxing treatment are lowered.
Also, with the density smaller than that under load condition of 1.961 KPa, the retention of impregnated coating composition in the cloth is reduced and the retention volume is also reduced, accordingly. As a result of this, such a cloth cannot wax the paintwork to a sufficient extent. Additionally, in the waxing work, the quantity of coating composition discharged from the cloth impregnated with the coating composition is increased and, as a result, surplus components adhere to the paintwork and thus the coating having even thickness cannot be formed on the paintwork. With the density of larger than that, the retention volume is reduced and thus the quantity of coating composition discharged from the cloth impregnated with the coating composition is reduced and, as a result, a sufficient quantity of components do not adhere to the paintwork.
The cloth can be used without any particular limitation, as long as it has a basis weight and a density in the range specified above. Preferably, the non-woven fabric is used. The non-woven fabrics that may be used include, for example, wet non-woven fabric, dry pulp non-woven fabric, dry non-woven fabric, spun-bonded non-woven fabric, melt-blow non-woven fabric and flash spun non-woven fabric.
To be more specific, the non-woven fabrics that may be used include, for example, 100% polyester, dry, needle-punched, non-woven fabric (basis weight of 110 g/m2 and density of 0.07 g/cm3 under load condition of 1.961 KPa), 100% rayon, dry, spun-lace non-woven fabric (basis weight of 40 g/m2 and density of 0.18 g/cm3 under load condition of 1.961 KPa), 100% nylon, melt-blow non-woven fabric (basis weight of 50 g/m2 and density of 0.15 g/cm3 under load condition of 1.961 KPa), 70% acryl and 30% polyester blended, wet, spun-lace, non-woven fabric (basis weight of 40 g/m2 and density of 0.15 g/cm3 under load condition of 1.961 KPa), 50% polypropylene and 50% polyester blended, dry, thermal-bonded, non-woven fabric (basis weight of 40 g/m2 and density of 0.12 g/cm3 under load condition of 1.961 KPa), 25% nylon, 25% polyethylene and 50% rayon blended, dry, chemical-bonded, non-woven fabric (basis weight of 40 g/m2 and density of 0.12 g/cm3 under load condition of 1.961 KPa) and 25% nylon, 25% polyethylene and 25% polyester and 25% rayon blended, dry, spun-lace, non-woven fabric (basis weight of 85 g/m2 and density of 0.17 g/cm3 under load condition of 1.961 KPa).
The methods of impregnating the cloth with the coating composition that may be used include, for example, a dip roll coater, a rotogravure roll coater, a spray coater, a reverse roll coater, a direct roll coater, a kiss roll coater, an inverse knife coater, an air knife coater, an opposite knife coater and a brush application. The coating cloth of the present invention can be produced by impregnating the coating composition in the fabric in any of those known methods. The coating composition is often made to shower over the fabric from above, the method of which is called a showering method.
The coating composition is impregnated in the cloth in the proportion of the coating composition being 1.0 to 5.0 times, or preferably 1.5 to 4.0 times, the cloth in weight.
The coating cloth of the present invention thus produced can be applied to the coating of paintworks in metals, plastics, ceramics and woods, without limiting to any specific paintwork. To be more specific, the coating cloth of the present invention can be applied to the coating of paintworks in vehicles, aircrafts, boats and ships, heavy machinery, machines in various industries, furniture, electrical household appliances and electrical equipment, and a variety of household appliances.
When the paintwork is treated by use of the coating cloth of the present invention, the paintwork is rubbed with the coating cloth of the invention until the paintwork is cleaned up so that the paintwork can be coated with the coating composition.
With the coating cloth of the present invention, the smooth rubbing work in the coating process can be ensured and also the good coating of even in coating thickness can be formed on the paintwork and thus the good water-repellent property and the good antifouling property can be developed. Particularly, when the coating composition is impregnated in the cloth in the form of water dispersion, polytetrafluoroethylene and perfluoropolyether are stably dispersed in water before the rubbing of the coating composition, while, once the coating composition is rubbed over the paintwork, they are allowed to adequately adhere to the paintwork by the rubbing force and are hardly reverted into water. Consequently, the quantity of adherence of the coating composition to the paintwork per quantity of coating composition applied thereto is large. Therefore, the coating cloth of the present invention can suitably be used as the coating cloth of the dry bright type requiring no wipe after a small quantity of coating composition is rubbed thereon. Further, the cloth impregnated with the coating composition in the form of water dispersion can dispense with the organic solvent, so good working conditions for environments and humans can be ensured.